I bought this for my 10 year old son and he had no problem building it. He loves it and plays with it often. He has taken it apart and built it in other ways. He would love to have more sets to add on to it. I feel an 8 year old could build this set with no problem. It is a very small set but that does not take away from the fun.
My son just turned 11 and he loves this set. He is a HUGE Minecraft & Lego fan so it was a no-brainer in my opinion. The set is pretty small and I would not (and did not) pay more than $35 for it. Only you can decide if it's worth the cost, but if your intended recipient isn't a Minecraft fan then I would suggest looking at another Lego set.
I wouldn't recommend it for any age, it's quite unremarkable for any age and definitely not worth $50. Once my son spent over an hour putting it together, he has even looked at it since. The Minecraft characters are a lot smaller than the typical Lego characters, so those aren't even worth collecting. Again, don't purchase this unless you've got $50 to throw out the window.